EVALUATING THE RELATIONSHIP AMONG LAND USE CHANGE, SEDIMENT AND NUTRIENT EXPORT, WITH NEARSHORE CORAL HEALTH IN SOUTHWESTERN PUERTO RICO

The coral reefs of Guánica Bay along the southwest coast of Puerto Rico are believed to be severely degraded due to influxes of sediment and nutrients from the adjacent Rio Loco watershed. Over the last several decades, land degradation in the headwater regions of the watershed, largely associated with agricultural and pastoral practices, has created an ideal situation for sediment mobilization triggered by intense precipitation events. This study seeks to evaluate the long-term relationship (1991-2015) between land cover and land use alteration with sediment and nutrient export in the Rio Loco watershed and nearshore coral health in the adjacent Guánica Bay through use of the following: 1) analysis of historical land use data from the USDA Forest Service, GAP Analysis and National Land Cover Database (NLCD), 2) calculation of sediment and nutrient yields using historical USGS datasets, and 3) determination of annual growth band width in previously collected coral cores (sp. Montastrea faveolata) from three near-shore reef sites in Guánica Bay. The sediment and nutrient flux data will also be compared with existing NOAA precipitation data for the same period to identify rainfall thresholds capable of producing large scale sediment export events. Data obtained from this study will be of great use to resource managers with regards to mitigation and/or conservation measures designed to protect coastal areas.